<?php

/**
 * Validates a number as defined by the CSS spec.
 */
class HTMLPurifier_AttrDef_CSS_Number extends HTMLPurifier_AttrDef
{
	
	/**
	 * Bool indicating whether or not only positive values allowed.
	 */
	var $non_negative = false;
	
	/**
	 * @param $non_negative Bool indicating whether negatives are forbidden
	 */
	function HTMLPurifier_AttrDef_CSS_Number($non_negative = false) {
		$this->non_negative = $non_negative;
	}
	
	/**
	 * @warning Some contexts do not pass $config, $context. These
	 *		  variables should not be used without checking HTMLPurifier_Length.
	 *		  This might not work properly in PHP4.
	 */
	function validate($number, $config, &$context) {
		
		$number = $this->parseCDATA($number);
		
		if ($number === '') return false;
		
		$sign = '';
		switch ($number[0]) {
			case '-':
				if ($this->non_negative) return false;
				$sign = '-';
			case '+':
				$number = substr($number, 1);
		}
		
		if (ctype_digit($number)) {
			$number = ltrim($number, '0');
			return $number ? $sign . $number : '0';
		}
		if (!strpos($number, '.')) return false;
		
		list($left, $right) = explode('.', $number, 2);
		
		if (!ctype_digit($left)) return false;
		$left = ltrim($left, '0');
		
		$right = rtrim($right, '0');
		
		if ($right === '') {
			return $left ? $sign . $left : '0';
		} elseif (!ctype_digit($right)) {
			return false;
		}
		
		return $sign . $left . '.' . $right;
		
	}
	
}

